Piston



P. M. FREER PISTON Feb. 11, 1930.

Original Filed Jan. 18. 1928 INVENTOR. p/fip/s 5??? Y A TTORNEYJ Patented Feb. 11, 1930 1 UNITED STATES PATENT OFFICE PHELPSM. FREER, OF DETROIT, MICHIGAN, ASSIGNO R, BY DIRECT AND MESNE ASSIGNMENTS, OF FIFTY-ONE PER CENT 'TO CHARLES H. LEWIS, OF CLEVELAND,

OHIO, AND FORTY-NINE PER CENT TO DETROIT AND SECURITY TRUST COMPANY, TRUSTEE, A CORPORATION OF MICHIGAN rrs'ron T Original application flled January 18 ,'1928,'Seria1 No. 247,605. Divided and this application filed March T w T 11, 1929. Serial No. 345,955. T

This invention relatesto improvements in pistons designed particularly for use in internal combustion engines, as described in the present specification and illustrated in the accompanying drawing which forms a part of the same, and is a division of my application for Letters Patent of the-United States forimprovements in pistons, filed January 18, 1928, and serially numbered 247,805.

The objects of the invention are tdprovide a composite piston comprising a head of light material having high heat conducting qualities, and a skirt of maximum wearing qualities joined to the head by asimple form of spring bracelet whichiurther serves to maintain the head and skirt in true concentric relationship. T

i In the drawings: T. j T T Fig. 1 isan elevational view of the piston with a ,portionot theskirt thereof broken awayto better illustrate the construction.

Fig. 2=isarside elevationdetail view of the head with onequarter thereof broken away, the head being: turned ninety degreesflfrom theviewshown in Fig. 1. T v

Fig. 3 is a side elevation view of the spring bracelet.

4 is aside elevationof the skirt memit ber with portions thereof broken away to betterillustrate the construction.

Fig. 5 is a sectional view taken as on the line 5'-5 of Fig. 1 showing the connection between the bracelet and the head member.

Fig. 6 is a fragmentary sectional view taken on the line 66 of Fig. 1, illustrating the relationship of certain bracelet fingers with cooperating notches formed in the skirt member.

Like numerals of reference indicate corresponding parts in each figure.

Referring to the drawings, the numeral 10 indicates the piston head, having the usual piston ring grooves 11, and also having the downwardly depending annular portion 12 terminating at or near the piston pin bosses 13, whereby the said bosses are adequately supported from the head.

The portion 12 of the head has an annular groove 14 cut therearound adjacent its lower end, and extends downwardly froma locking shoulder 15.

The head as described is preferably made of cast aluminum or other light alloy having maximum heat conducting qualities, while the skirt 16 is made of a metal such as a cast nickel iron alloy or the like, which possesses high wearingqualities and a very low coefficient of expansion. j

The skirt 16 is made of a plain cylindrical form having a small ledge'or inwardly extending flange 17 around the bottom for rein forcing purposes,and likewise an inwardly extending flange 18 around the top, the flange 18 being finished on its under side 19 with a bevel of a definite angle for purposes as hereinafter described. I

. The head 10 and skirt 16 are cast other wise formed and finishedas separate pieces and are then joined by a spring bracelet having a split annular inturned lower end21 and upwardly and outwardly extending fingers 22, 23 and 24:, the fingers 22 being slightly longer than the fingers 23, sothat the bracelet may be sprung around the lower part 12 of the head 10 similar to a piston ring, with the lower inturned portion 20 fitting snugly in the groove 14 in the head 10. The flange 18 of the skirt 16 is notched out as at 36 at points corresponding with the spacing of the fingers 2410f the bracelet so as to receive such fingers therein, for a purpose to be hereinafter described. V T T To assemble the parts, theskirt is pressed upwardly against the head, to which the bracelet is assembled, with the fingers 24 in proper alignment with the notches 86, causing thefingers 22 and 23 of the bracelet 20 to spring inwardly until the flange 18 passes the ends of the fingers 22 and 28, and abuts against the flange 15 on the head, at which time the fingers 22 and 23 are of such a length that they will just have cleared the flange 18,.

the skirt due to unequal expansion between a normally cold temperature and a temperature that may be obtained when the piston has been running under excessive compression conditions in the engine cylinder.

To maintain true concentricity between the head and skirt at all times, the extra long fingers 24 on the bracelet, and cooperating notches 36 in the flange 18 of the skirt 16 are provided. The side walls of the grooves 36 are preferably tapered so that the fingers 24 in dropping into them upon assembly of the head and skirt, will engage the sides of the respective grooves before they can reach the bottoms thereof. This insures a close fit of the fingers 24 with the sides of the grooves so as to prevent any possible movement of the head relative to the skirt in a direction perpendicular to a line connecting diametrically opposite fingers 24 in a plane parallel to the piston face. This construction permits relativel wide manufacturing tolerances in the widt of the fingers 24 and grooves 36 without detracting from the proper relationship which must be maintained between the head and skirt for optimum operating results.

The portion of the bracelet preferably is so constructed as to be forced home against the bottom of the groove 14 in the head 10 when the skirt is assembled to the head, and for this reason, there is little liability of possible rotation of the bracelet in the groove 14, but where more positive means for insuring against such relative movement is desired, inwardlyextending projections such as 37 may be provided on the portion 20 of the bracelet,

which will be forced into the softer metal of the head when the bracelet 37 is placed under compression upon assembly of the head and skirt, as above described. These pro ections positively insure against relative movements between the bracelet and the head, and inasmuch as the fingers 24 are received within the notches 36, no relative rotational movement is permitted between the head and skirt.

Formal changes may be made in the specific embodiment of the invention described Without departing from the spirit or substance of the broad invention, the scope of which is commensurate with the appended claims.

' What I claim is: 1. A piston comprising a pair of members secured together in sleeved relationship by means of a collar provided with resilient fingers, and means for preventing rotation of one of said members relative to said collar comprising a radially extending projection carried by said fingers received in a depression in one of said members.

2. A piston comprising a pair of members secured together in sleeved relationship by means of a collar provided with resilient fingers certain of said fingers engaging one of said members to lock it against rotation relative thereto, and means for preventing said collar from rotating relative to the other of said members.

3. A piston comprising a pair of members secured together in sleeved relationship, a ring-like member encircling one of said pair of members and held against rotation thereon, and means on said ring-like member coacting with the other of said pair of members to lock it against rotation relative to said ring-like member.

4. A piston comprising a pair of members secured together in sleeved relationship, a ring encircling one of said members and having projections received therein for preventing rotation of said ring relative to said member, and co-acting projections and depressions on the other of said members and said ring for preventing relative rotation between them.

5. A piston comprising a pair of members secured together in sleeved relationship, a ring secured against rotational movement relative to one of said members, the other of said members being provided with a notch, and a finger on said ring engaged in said notch.

6. A piston comprising a pair of members secured together in sleeved relationship, a ring secured against rotational movement relative to one of said members, the other of said members having substantially oppositely disposed notches therein, and fingers on said ring engaged in said notches.

7 A piston comprising a pair ofmembers arranged in sleeved relatlonship with respect to each other, one of said members being provided with an inwardly projecting circumferential flange, a series of connected spring fingers carried by the other'of said members and arranged to co-act with said flange to secure said members against separation, said flange being notched, and other spring fingers engaged in said notches to prevent rotation of one of said members relative to the other thereof.

8. A piston comprising a head member and a skirt member secured together in sleeved relationship by a plurality of spring fingers, and means for preventing rotational movement of one of said members relative to the other thereof comprising a finger of abnormal length received in a notch in one of said members.

9. A piston comprising a pair of members secured together in sleeved relationship by means of a collar provided with resilient fingers, and means for preventing rotation of one of said members relative to said collar comprising an abnormally long finger on said collar and a cooperating notch in one of said members.

10. In combination, a iston comprising a head and a skirt arrange in sleeved relationship, a circumferential groove in said head, a split ring received in said groove, inwardly extending projections on said ring, spring fingersearried by said ring for engagement with said skirt whereby to secure said head and skirt against separation, said fingers being pressed radially inwardly in assembling said head and skirt whereby said ring is con- 1 tractecl and said projections are forced into the metal of said head at the bottom of said groove.

PHELPS M. FREER. 

